Coextruded profiled webs

ABSTRACT

A method that includes coextruding two or more thermoplastic resin streams through a profiled die plate, which die plate is shaped to form a nonplanar film (three dimensional) preferably with a regularly oscillating peak and valley structure that oscillates from a top surface to a bottom surface forming longitudinally extending ridges on both faces of the film. The film is formed by coextruding the film through the oscillating die plate opening causing partitioning of the resins in different zones in the width direction of the film. Flattening of the film results in a film with side-by-side zones formed of different polymers or relative proportions of polymers.

BACKGROUND OF THE INVENTION

Coextrusion of multiple polymeric components into a single layer castfilm is relatively common in the art. Often, multiple polymeric flowstreams are combined in a die or feedblock in a layered fashion toprovide a top to bottom multilayer film. The diverse polymer flowsteamsare typically combined in a feedblock section or the like and then flowin a layered configuration into a conventional coat hanger diearrangement, where the flowstreams flatten out into a film-likeflowstream and are extruded onto a casting roll or the like. Thisarrangement creates films where the polymers form into layers in thethickness dimension.

Alternatively, it is also proposed to provide more complicatedcoextruded film structures where the layers are partitioned not ascoextensive layers in the thickness direction but partitioned along thewidth of the film. An example is where the polymers are partitioned in aside-by-side configuration or variations thereof to provide discreteincluded zones of a first polymer within a continuous matrix of a secondpolymer. U.S. Pat. No. 4,426,344 describes a complicated feedblockmethod which takes two coextruded melt streams initially arranged in thethickness direction, with a zig-zag interface, and redirects the top tobottom layered polymer flows into a side-by-side arrangement resultingin a film having a sinusoidal or zig-zag interface, with different zonesin the width direction. Although the two halves were indicated as beingformed of identical materials it is conceivable that different materialscould be employed in the two halves though this is not specificallytaught.

Japanese Kokai No. 8-187113 discloses the possibility of side-by-sidecoextrusion although a specific method for achieving this is notspecifically disclosed. U.S. Pat. No. 6,221,483 also discloses aside-by-side coextrusion of an elastic material and an inelasticmaterial for use in a diaper fastening tab. The elastic materials areintermittently spaced by inelastic material. The side-by-sidearrangement is achieved by using an insert in a conventional two layerslot die which blocks off alternating lanes of the elastic and inelasticmaterials coming from the two slots and brings them together in analternating fashion. This method requires that extreme pressure beapplied to prevent leakage of the respective materials due to theirdifferences in melt flow. The two materials would still tend to flowlaterally in the die once they pass the insert. U.S. Pat. No. 4,787,897also discloses a side-by-side arrangement of multiple layers, althoughin this case three zones are disclosed. There are two outer inelasticzones with a single inner elastic zone. The inner elastic zone iscreated somehow by coalescence of a single elastic melt stream in a die,but it is unclear how this is done. U.S. Pat. No. 5,429,856 disclosesthe possibility of creating discrete elastic strands or zones within aninelastic matrix by an inclusion coextrusion technique using aCloeren-type three layer die feeding discrete strands of elastic intothe center melt stream with two inelastic outer layers sandwiching thediscrete elastic flowstreams.

All the above described methods describe methods for forming films.Anything other than simple multiple layers in the thickness dimensionsuch as side-by-side layering or more complex layer arrangements, arecreated by modifications of either of the feedblock or the die whereinpolymer melt flows are diverted or redirected or the like. Theseapproaches are somewhat problematic in an enclosed die or feedblock.They require that melt streams of different polymeric materials beexposed to complex nonlinear flow patterns within the body of the die ormanifold. This can result in complex flow interactions and problems withresidue build up and the need for routine disassembling and cleaning.Also different materials do not generally combine in a predictablemanner as the flow characteristics of the polymers in the die ormanifold are not always the same. When the materials are combined,complex flow interactions occur between the convergence zones for thepolymers and the extruder die lip resulting in films other than thosespecifically desired. The present invention addresses some of theseproblems by providing for side-by-side type relative layering inextruded films by altering the discrete thermoplastic resin streams in afilm extrudate immediately at the die lip.

BRIEF DESCRIPTION OF THE INVENTION

The present invention is directed at a coextruded polymer film withvarying polymer zones in the width or cross-section direction formedfrom a profile extruded film. The profile extruded film is threedimensional and has a first face and a second face. The polymer film iscoextruded from a conventional multilayer or multi-component die andthen the flow is partitioned at the die face by a profiled die platehaving a profiled opening oscillating from an upper region to a lowerregion on either side of a center line. The film is characterized by twoor more side-by-side zones with different polymers or relativeproportions of polymers and is nonplanar. Generally, at any given planeof the nonplanar film, the polymer or relative proportions of polymer inthat plane will be substantially identical when the oscillatingstructure is substantially regular.

The preferred method generally includes coextruding two or morethermoplastic resin streams through the profiled die plate, which dieplate is shaped to form a nonplanar film (three dimensional) preferablywith a regularly oscillating peak and valley structure that oscillatesfrom a top surface to a bottom surface forming longitudinally extendingridges on both faces of the film. The film is formed by coextruding thefilm through the oscillating die plate opening causing partitioning ofthe resins in different zones in the width direction of the film.Flattening of the film results in a film with side-by-side zones formedof different polymers or relative proportions of polymers.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described with reference to theaccompanying drawings wherein like reference numerals refer to likeparts in the several views, and wherein:

FIG. 1 is a schematic view of a method of forming the invention film.

FIG. 2 is a cross-sectional view of a die plate used to form a precursorfilm used in accordance with the present invention.

FIG. 3 is a perspective view of a precursor film used in accordance withthe present invention.

FIG. 3 a is a perspective view of a precursor film used in accordancewith the present invention.

FIG. 4 is a cross-sectional view of the FIG. 3 film flattened to aplanar form.

FIGS. 5 and 6 are perspective views of the FIG. 3 film cut on one faceat regular intervals in oscillating form and flattened form.

FIG. 7 is a perspective view of a netting in accordance with the presentinvention produced from the FIG. 6 cut film.

FIG. 8 is a perspective view of a three layer film embodiment inaccordance with the present invention.

FIG. 8 a is a cross-sectional view of the FIG. 8 film flattened to aplanar form.

FIG. 8 b is a cross-sectional view of the FIG. 8 a film oriented in thecross-direction

FIG. 9 is a perspective view of the FIG. 8 film cut on one face atregular intervals.

FIG. 10 is a perspective view of the FIG. 9 cut film oriented in thelength direction to form a netting.

FIG. 11 is a cross-sectional view of a die plate used to form aprecursor film used in accordance with the present invention.

FIG. 12 is a perspective view of a film embodiment in accordance withthe present invention having hook elements.

FIG. 13 is a cross-sectional view of the FIG. 12 film flattened to aplanar form.

FIG. 14 is a perspective view of the FIG. 12 film cut on one face atregular intervals.

FIG. 14 a is a perspective view of a netting in accordance with thepresent invention.

FIG. 15 is a perspective view of a two layer film in accordance with thepresent invention.

FIG. 16 is a perspective view of the FIG. 15 film cut at regularintervals on one face.

FIG. 17 is a perspective view of the FIG. 16 cut film length oriented toform a netting.

FIG. 18 is a perspective view of a film with three layers in accordancewith the present invention.

FIG. 19 is a perspective view of the FIG. 18 film cut at an angle to theridges.

FIG. 20 is a perspective view of the netting produced from the FIG. 19cut film.

FIG. 21 is a cross-sectional view of a die plate used to form analternative embodiment film in accordance with the present invention.

FIG. 21 a is a perspective view of a film produced with the FIG. 21 dieplate.

FIG. 22 is a perspective view of the FIG. 21 a film cut at alternatingdepths on one face.

FIG. 23 is a perspective view of a netting produced from the FIG. 22 cutfilm.

FIG. 24 is a perspective view of a film in accordance with the presentinvention.

FIG. 25 is a view of the FIG. 24 film cut on both faces.

FIG. 26 is perspective view of a netting produced from the FIG. 25 cutfilm.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A method for forming a coextruded film of the invention is schematicallyillustrated in FIG. 1. Generally, the method includes first extruding aprofiled multilayer film through a die plate 1 and 100, shown in FIGS. 2and 11. The thermoplastic resin is delivered from conventional filmextruders 51, 151 through the die 52 having die plate 1, 100 with aprofiled non-rectilinear opening 2, 102 by non-rectilinear it is meantthat the die plate opening as a whole is in a form other than arectangle however portions of the die openings could be rectilinear. Thedie plate can be cut, for example, by electron discharge machining,shaped to form the nonplanar film 10, 110 which optionally (as per FIG.12) can have elongate spaced structures 7 extending along one or bothsurfaces 3 and 4 of the film 10. If elongate spaced structures 7 areprovided on one or both surfaces 3 and 4 of the film 10, the structures7 can have any predetermined shape, including that of hook portions ormembers. The nonplanar film 10, 110 generally is pulled around rollers55 through a quench tank 56 filled with a cooling liquid (e.g., water),after which the film 10, 110 can be transversely slit or cut at spacedlocations 20, 120 along its length by a cutter 58 to form discrete cutportions of the film 10, 110 forming a netting precursor film as shownin FIGS. 5 and 14. Alternatively, the film can be rendered planar byheat treatment, such as in a heated nip or the like. While FIGS. 2 and21 show die plates 100, 300 having profiled cut openings 102, 302 thatare uniform in width across the die plate, it is also possible that thewidth can be changed across the die face if so desired. The thickness“t”, as shown in FIG. 3 a, of the extruded film can be constant or canvary across the film by varying the width of the profiled cut openings.

The coextruded films shown in FIGS. 3 and 12 are two layerconstructions. A conventional two layer precursor film flowstream havingan upper and lower zone is fed from the die into the die plates 1 or 100(having a peak and valley shape) which causes the upper polymer flowfilm layer 9, 109 to collect in the upper half 6, 106 of the nonplanarfilm and the lower polymer flow film layer 8, 108 to collect in thelower half 5, 105 of the nonplanar film. The division of the twomulti-stream polymer film layers between the upper and lower halves ofthe extruded nonplanar film would depend on their relative mass flowrates. The upper film layer 9, 109 could extend into the lower half 5 or105 of the nonplanar film or the lower film layer 8, 108 could extendinto the upper half 6, 106 of the nonplanar film. With a two layerconstruction, the upper and lower layers tend to disproportionallypartition in a planar manner which results in distinct side-by-sidepartitioning in the finished film 110′ or 10′ without the need forcomplex flow diversions in the feedblock or die bodies. The polymershave been partitioned along the width-wise extension of the film 10′ and110′ such that the proportion of the two (or more) polymers variesacross film width. In the two layer embodiments, this variation is suchthat there is a substantially complete partitioning of the polymers fromsubstantially 100 percent of the first polymer layer in a firstwidth-wise zone to substantially 100 percent of the second polymer layerin a second width-wise zone. With three or more polymer layers at leastone of the polymer layers, generally will vary in thickness across thetransverse direction of the web. A polymer layer varying in thicknesswill generally comprise 0-90% of the total film thickness. Each of thelayers can comprise from 0-100% of the total thickness of the film atany point across the width (Y-direction) of the film. The polymer layervarying in thickness will generally vary by at least 10 percentcomparing the thickest region to the thinnest region or alternatively,by at least 20 percent or at least 50 percent. The partitioning will bedictated by the relative proportions of the precursor polymer filmlayers and the shape of the opening of the die plates 1 or 100. With adie plate having a regularly oscillating opening, the partitioning willresult in a nonplanar film as shown in FIG. 3 a where at a given planethe relative proportions of the polymers will be substantially identicalassuming a coextruded polymer flow stream with constant ratios of thepolymers across its width. Where the die plate openings vary in eitherthickness T′, angle “β” amplitude “H”, wavelength “W” or any combinationthereof, as shown in FIG. 2, the partitioning of the polymer layers willvary but the flow streams will still partition between the peaks andvalleys of the opening of the die plates. The degree of partitioningwill also depend on the angle β between legs of the peak and valleyopenings of the die plate where the angle β is less than 90 degrees atleast one of the layers will tend to be completely portioned such thatit is discontinuously distributed in the formed film. This isparticularly true where there is an outer film layer that forms lessthan 50 percent of the film. When the angle β is greater than 90degrees, the layers tend to partition such that there is nodiscontinuous layers particularly where a layer is 50 percent or less ofthe film. Generally the angle β ranges from 170° to 5°, 140° to 10°,110° to 20°, or 90° to 30°. The peak and valley structure of the openingof the die plates would generally correspond to the desired profiledfilm. The peak and valley structures could be regular oscillating curvesas shown, step-function curves, or any other variation.

The film 10, 110 as shown in FIGS. 12 and 3 has a first top face 4, 104and a second bottom face 3, 103 with a film thickness 14, 114 of from 25microns to 1000 microns, preferably 50 microns to 500 microns. The film10, 110 is nonplanar where the film oscillates, such as by peaks andvalleys in the form of substantially continuous ridges, from a firstupper plane 12, 112 to a second lower plane 13, 113. By this, it ismeant the film itself, or the continuous film backing not structures onthe film surface, is nonplanar and oscillates from the upper plane tothe lower plane. The film backing oscillates around a midline 15, 115and the nonplanar film is characterized by a first half 6, 106 extendingon one side of the midline 15, 115 and a second half 5, 105 extending onthe opposing side of the midline 15, 115. The peaks of the ridges on thefilm backing or the top of structure 45, 145, on the top face of thefilm, generally extend at least to the upper plane 12, 112. The peaks ofthe ridges on the film backing, or individual peaks 45, 145 canterminate below or above the upper plane 12, 112 preferably at a pointbetween the midline 15, 115 and the top plane 12, 112. The peaks 17, 117on the bottom face 3, 103 of the film backing also extend generally atleast to the lower plane 13, 113. However, again the film backing planeor individual peaks can terminate above or below the lower plane 13, 113and preferably between the midline 15, 115 and the lower plane 13, 113.The peaks generally alternate from the lower plane 13, 113 to the upperplane 12, 112 but multiple peaks can extend, in a row, to either theupper plane or the lower plane without extending to the other half ofthe nonplanar film face by having the intermediate peaks only extendingto the midline or below the midline. Generally, the nonplanar film willhave at least about 2 peaks (45, 145 and/or 17, 117) per linearcentimeter (cm) and preferably at least 5 extending up to 50 peaks perlinear centimeter. Each peak can extend past the midline of the film toan extent such that the underside 18, 118 of the peak extends past theunderside 19, 119 of the adjacent opposing peak by at least 10 microns,preferably at least 50 microns. The distance 6, 106 or 5, 105 betweenthe midline and the upper plane 12, 112 or lower plane 13, 113 isgenerally about 50 microns to 2000 microns preferably about 100 micronsto 1000 microns.

With cut films, as shown in FIGS. 14 and 5, the distance between thecuts 20, 120 corresponds to about the desired width 21, 121 of the cutportions 31, 131 to be formed, as is shown, for example, in FIGS. 7 and14 a. The cuts 20, 120 can be at any desired angle, generally from 30°to 150°, from the lengthwise extension of the film (X-direction).Optionally, the film can be stretched prior to cutting to providefurther molecular orientation to the polymeric film 10, 110 and reducingthe thickness 14, 114 of the film 10, 110 and any structures on thefilm. The cutter can cut using any conventional means such asreciprocating or rotating blades, lasers, or water jets, howeverpreferably the cutter uses blades oriented at an angle of about 60 to 90degrees with respect to lengthwise extension of the film 10, 110.

The film of FIGS. 3 and 12 can also be formed into nettings. In thisembodiment, the films 10 or 110 are cut on either the upper face 4, 104or the lower face 3, 103 from the upper plane 12, 112 toward the midline15, 115 or from the lower plane 13, 113 toward the midline 15, 115, asshown, for example, in FIGS. 14 and 5. The cuts 20 or 120 extend fromthe upper or lower plane at least through the undersides 18, 118 or 19,119 of the peaks. At least some of the peaks 45, 145 on the face are cutand preferably all or substantially all of the peaks are cut. The cuts20 or 120 will preferably at least extend to the midline of a filmbacking. Generally the cuts can extend so that they go to the undersidesof the opposing peaks. Preferably, the cuts will terminate beforereaching substantially all of the undersides of the opposing peaks toavoid severing the film. Undersides of the peaks on one face will formthe valleys of the opposing face. In an alternative embodiment, the filmcan be cut on both faces as described above as long as the cuts onopposing faces are offset so as not to completely sever the film. Thedistance between cuts 21 and 121, which form the cut portions 31 and131, is generally 100 microns to 1000 microns, preferably from 200microns to 500 microns. The cut portions 31, 131 form the strands 46,146 extending in the cross-direction of the netting 40, 140. The strands41, 141 extending in the lengthwise direction are formed by the uncutportions of the film. These lengthwise strands are generally continuouswhen the film backing is cut on only one face. At least some of thecross direction strands 46 and 146 are at least in part generally alwayscontinuous when the cuts are continuous.

After cutting of the film 10, 110 the film can be flattened as in theFIG. 6 embodiment or left as an oscillating film as in the FIG. 14embodiment. The cut film can then be longitudinally stretched at astretch ratio of 2:1 to 4:1, and preferably at a stretch ratio of atleast about 3:1, preferably between a first pair of nip rollers 60 and61 and a second pair of nip rollers 62 and 63 driven at differentsurface speeds. This forms the open three dimensional netting shown ine.g., FIGS. 14 a and 7. Roller 61 is typically heated to heat the filmprior to stretching, and roller 62 is typically chilled to stabilize thestretched film. Optionally, the film can also be transversely stretchedto provide orientation to the film in the cross direction and flattenthe profile of the netting formed. The film could also be stretched inother directions or in multiple directions. The above stretching methodwould apply to all embodiments of the invention. With the films cut ononly one face, the open areas 43 and 143 generally are separated bylinear strands 41, 141, which strands have a non-rectilinearcross-section or are nonplanar along their length or both. Thetransverse strands are generally nonplanar, although they can berectilinear in cross-section. Nonplanar strands or a nonplanar nettingprovides for a more flexible netting which creates breathability boththrough the film (by the open area of the netting) and along the planeof the reticulated netting, due to its nonplanar nature. The open areasgenerally comprise about at least 50 percent of the surface area of thenetting and preferably at least 60 percent. The surface area of thenetting is the planar cross-sectional area of the netting in the X-Yplane. This large percentage open area creates an extremely flexible andbreathable netting. The hook heads formed on hook nettings arepreferably smaller than the individual openings in the netting in thedirection parallel with the hook head overhangs such that the hooknetting is non-self engaging. In the hook netting embodiment of FIG. 14a this would be the transverse direction Y.

Stretching causes spaces 43 and 143 between the cut portions 31 and 131of the film and creates the longitudinal strands 41 and 141 byorientation of the uncut portions of the film. The transverse strands44, 144 are formed by interconnected cut portions each of which has legportions which join at the peak 45, 145. The leg portions of adjacentcut portions are connected by strands (e.g., 41 and 141) or the uncutfilm portions.

FIGS. 14 a and 7, 10, 17, 20, 23, 26 are exemplary polymeric mesh ornettings, which can be produced, according to the present invention,generally designated by the reference numerals 40, 140. The nettingcomprises upper 46, 146 and lower 47, 147 major surfaces. The cut ridgeson the upper surface 46 form a multiplicity of hook members 48.

The netting is formed having transversely extending strands that arecreated by the cut portions of the three-dimensional film extending inthe cross direction and longitudinally extending strands created by atleast in part by uncut portions of the film. When tension or stretchingis applied to the film in the lengthwise direction, the cut portions 31,131 of the film separate, as shown in the embodiments of FIGS. 14 a and7. When the film is cut on only one face, the uncut portions of thefilm, between cut lines, are aligned in the lengthwise directionresulting in formation of linear strands 41, 141 extending in thelengthwise direction upon stretching or tensioning of the cut film. Thetransverse strands 44, 144 are created by the cut portions in theembodiments shown in FIGS. 14 a and 7. The cut portions connect thelongitudinal strands 41, 141 formed by the uncut portions. In the FIG.14 a embodiment, the hook elements formed on the cut portions form areticulated netting having hook engaging elements providing abreathable, compliant and deformable hook netting. A hook netting ofthis type is extremely desirable for limited use articles such asdisposable absorbent articles (e.g., diapers, feminine hygiene articles,limited use garments and the like).

The netting is characterized by having no bond points or bondingmaterial at the cross-over points of the transverse and longitudinalstrands. The netting is integrally formed of a continuous material. Theconnection between the strand elements is created in the film formationprocess where the strands are created by cutting of an integral film. Assuch the netting at the cross-over points is a continuous homogeneouspolymeric phase. Namely, there are no interfacial boundaries caused byfusion or bonding of separate strand elements at the strand cross-overpoints. Preferably, at least one set of strands has molecularorientation caused by stretching; this generally would be thelongitudinal strands. These oriented strands could be of anycross-sectional profile and would tend to become rounded due to polymerflow during stretching. Orientation creates strength in these strandsproviding a dimensionally stable web in the direction of orientationwith continuous linear strands. Unoriented strands are generallyrectilinear in cross-section due to the cutting operation. The two setsof strands generally will intersect a planar face of the netting at anangle α, in the Z or thickness direction, of greater than zero (0)generally 20 degrees to 70 degrees, preferably 30 degrees to 60 degrees.

Formed netting can also be heat treated preferably by a non-contact heatsource. The temperature and duration of the heating should be selectedto cause shrinkage or thickness reduction of at least the hook head byfrom 5 to 90 percent. The heating is preferably accomplished using anon-contact heating source which can include radiant, hot air, flame,UV, microwave, ultrasonics or focused IR heat lamps. This heat treatingcan be over the entire strip containing the formed hook portions or canbe over only a portion or zone of the strip. Different portions of thestrip can be heat treated to more or less degrees of treatment.

FIG. 8 is an alternative embodiment of the FIG. 3 film 30 formed withthree polymer layers 37, 38 and 39. This again would result in unequalpartitioning of these three layers across the widthwise dimension of thefilm 30 when extruded through the profiled die plate 100 of FIG. 2. Thepartitioning is most extreme with the outermost layers adjacent thepeaks and valleys of the die plate. This is due to pooling of theoutermost layers in the peak and valley regions while the center polymerflow gets generally equally distributed. This can be seen more clearlyin FIG. 8 a where the FIG. 8 film 30 has been flattened into a planarfilm 30′. The three layers 31, 32 and 33 vary in thickness across thewidth of the film such that the upper film layer 37 goes from a maximum31′ to a minimum of 31 from a peak 34 to a valley 35 and the lower filmlayer 38 goes from a maximum thickness 33′ to a minimum thickness 33″from a peak 34′ to a valley 35′. The middle layer 32 remainssubstantially consistent in thickness 32′. The film 30 could then bestretched or oriented in the lengthwise or width dimension as shown inFIG. 8 b resulting in a thinning of the layers 37′, 38′ and 39′. FIG. 8b depicts the FIG. 8 a film after it has been stretched in thetransverse direction.

The FIG. 9 embodiment is identical to the FIG. 5 embodiment but uses thethree layer film of FIG. 8. The resulting netting, 410 as shown in FIG.10 has been stretched while the film is still in its profiled non-planarform. It could be flattened before or after stretching. Due to thedissimilar partitioning of the layers 37 and 38, the peak regions 440and valley regions 450 will have different properties than themid-region 460, between the peak and valley regions, which valleyregions have taken the form of continuous strands.

FIGS. 15 and 16 are embodiments similar to that of FIG. 5 but where thecuts 220 extend only partially through the upper polymer layer 206leaving a small portion 201 uncut. This allows a small portion of theupper polymer layer 206 to modify the behavior of the lower polymerlayer 209 when the cut film 210′ is stretched as shown in FIG. 17. Thissmall portion 201′ of the first polymer layer can, for example, create areinforcing effect if the lower polymer layer is an elastomeric polymerand the upper layer is relatively inelastic polymer. This wouldstabilize the cut film 210′ prior to orientation in the lengthwisedimension to allow for handling but allow the elastic behavior to beutilized following a stretch activation. Following a stretch activation,the relatively inelastic uncut material 201 would permanently deform. Ifthe upper polymer layer 206 were an elastomeric layer and the lowerlayer 209 was relatively inelastic, the uncut elastic region 201 wouldallow the elastic material to be more securely bonded to the lowerinelastic layer 209 following orientation of the cut film 210′ intonetting 210″.

FIG. 18 is the FIG. 8 film which is then cut in accordance with the cutpattern shown in FIG. 19. This embodiment is substantially the same asthat of FIGS. 5 and 6 except that the cuts 120″ are at an angle that isrelatively non-parallel to the transverse direction of the film 110″.This film when longitudinally stretched (the lengthwise direction)results in a netting such as shown in FIG. 20 resulting in spaces 143″between the cut portion 131″ and longitudinal strands 141″. Thetransverse strands 144″ are formed by interconnected cut portions 131″each of which has leg portions which join at the peaks 145″ and at theuncut film portion 141″. The spaces 143″ are staggered and aligned inthe direction of the cuts as are the transverse strands 144″.

FIG. 21 is an alternative die plate 300 with a cutout 302 shaped to forma precursor film as shown in FIG. 21 a having an upper plane 312 and alower plane 307. In this embodiment, some of the ridges 345 are largerthan others with intermediate ridges 355 having peaks terminating belowthe upper plane 312 but above the midline 315. This film is then cutwith multiple cuts 322, 320 on one face at varying depths as shown inFIG. 22 cut from the upper face 304 or upper plane towards the midline315 having an upper half 306 and lower half 305. The lower face 303 isuncut. The deeper cuts 320 extend from the upper plane at least throughthe undersides of the intermediate ridges 355. The lower ridges 317 areuncut with the cuts terminating prior to the underside 319 of the lowerridges 317. The shallow cuts 322 only cut the larger ridges 345resulting in some of the larger ridges 345 having more cuts and atdifferent depths. This results in a netting such as shown in FIG. 23with many different sizes and shapes of spaces 343, between the variouscut portions 331. The transverse strands 344 are similar to those of theembodiment of FIGS. 5 and 6 but are created by the deepest and the mostwidely spaced cuts.

FIG. 24 is the FIG. 18 precursor film, which is then cut on oppositefilm faces where the cuts are substantially nonoverlapping. This resultsin longitudinal strands formed primarily by the uncut portions. The cuts461 and 462 are on either face and are equally spaced and offset. Whenthis embodiment cut film, as shown in FIG. 25, is longitudinallystretched the resulting netting is as shown in FIG. 26. In thisembodiment, the longitudinal strands 470 are generally formed from theuncut portions 464 and 463 extending in the Z-direction. The spaces 443and 483 are on different planes. This is a version of the FIG. 10netting with spaces on either face but with discontinuous longitudinalstrands. Longitudinal strand segments would tend to be oriented.

Suitable polymeric materials from which the coextruded film of theinvention can be made include thermoplastic resins comprisingpolyolefins, e.g. polypropylene and polyethylene, polyvinyl chloride,polystyrene, nylons, polyester such as polyethylene terephthalate andthe like and copolymers and blends thereof. Preferably the resin is apolypropylene, polyethylene, polypropylene-polyethylene copolymer orblends thereof.

The multilayer construction can utilize any multilayer or multicomponentfilm extrusion process such as disclosed in U.S. Pat. Nos. 5,501,675;5,462,708; 5,354,597 and 5,344,691, the substance of which aresubstantially incorporated herein by reference. These references teachvarious forms of multilayer or coextruded elastomeric laminates, with atleast one elastic layer and either one or two relatively inelasticlayers. A multilayer film, however, could also be formed of two or moreelastic layers or two or more inelastic layers, or any combinationthereof, utilizing these known multilayer multicomponent coextrusiontechniques.

Inelastic layers are preferably formed of semicrystalline or amorphouspolymers or blends. Inelastic layers can be polyolefinic, formedpredominately of polymers such as polyethylene, polypropylene,polybutylene, or polyethylene-polypropylene copolymer.

Elastomeric materials which can be extruded into film include ABA blockcopolymers, polyurethanes, polyolefin elastomers, polyurethaneelastomers, EPDM elastomers, metallocene polyolefin elastomers,polyamide elastomers, ethylene vinyl acetate elastomers, polyesterelastomers, or the like. An ABA block copolymer elastomer generally isone where the A blocks are polyvinyl arene, preferably polystyrene, andthe B blocks are conjugated dienes specifically lower alkylene diene.The A block is generally formed predominately of monoalkylene arenes,preferably styrenic moieties and most preferably styrene, having a blockmolecular weight distribution between 4,000 and 50,000. The B block(s)is generally formed predominately of conjugated dienes, and has anaverage molecular weight of from between about 5,000 to 500,000, which Bblock(s) monomers can be further hydrogenated or functionalized. The Aand B blocks are conventionally configured in linear, radial or starconfiguration, among others, where the block copolymer contains at leastone A block and one B block, but preferably contains multiple A and/or Bblocks, which blocks may be the same or different. A typical blockcopolymer of this type is a linear ABA block copolymer where the Ablocks may be the same or different, or multi-block (block copolymershaving more than three blocks) copolymers having predominately Aterminal blocks. These multi-block copolymers can also contain a certainproportion of AB diblock copolymer. AB diblock copolymer tends to form amore tacky elastomeric film layer. Other elastomers can be blended witha block copolymer elastomer(s) provided that they do not adverselyaffect the elastomeric properties of the elastic film material. A blockscan also be formed from alphamethyl styrene, t-butyl styrene and otherpredominately alkylated styrenes, as well as mixtures and copolymersthereof. The B block can generally be formed from isoprene,1,3-butadiene or ethylene-butylene monomers, however, preferably isisoprene or 1,3-butadiene.

With all multilayer embodiments, layers could be used to providespecific functional properties in one or both directions of the filmsuch as elasticity, softness, hardness, stiffness, bendability,roughness or the like. The layers can be directed at different locationsin the Z direction that are formed of different materials creating afilm with cross-direction variation in properties such as describedabove.

Hook Dimensions

The dimensions of the reticulated webs were measured using a Leicamicroscope equipped with a zoom lens at a magnification of approximately25×. The samples were placed on a x-y moveable stage and measured viastage movement to the nearest micron. A minimum of 3 replicates wereused and averaged for each dimension.

EXAMPLE 1

A coextruded profiled web was made using apparatus similar to that shownin FIG. 1 except three extruders were used to produce a 3 layerstructure consisting of a first ‘A’ white layer, a second ‘B’ red layerand a third ‘C’ red layer. The first layer was produced with apolypropylene/polyethylene impact copolymer (99% 7523, 4.0 MFI, BasellPolyolefins Company, Hoofddorp, Netherlands) and 1% white TiO2polypropylene-based color concentrate. The second and third layers wereproduced with 98% 7523 polypropylene/polyethylene impact copolymer and2% red polypropylene-based color concentrate. A 6.35 cm single screwextruder was used to supply 7523 copolymer for the first layer, a 3.81cm single screw extruder was used to supply 7523 copolymer for thesecond layer and a 2.54 cm single screw extruder was used to supply 7523copolymer for the third layer. The barrel temperature profiles of allthree extruders were approximately the same from a feed zone of 215° C.gradually increasing to 238° C. at the end of the barrels. The meltstreams of the three extruders were fed to a ABC three layer coextrusionfeedblock (Cloeren Co., Orange, Tex.). The feedblock was mounted onto a20 cm die equipped with a profiled die lip similar to that shown in FIG.2. The feedblock and die were maintained at 238° C. The die lip wasmachined such that the angle (β) between two successive channel segmentswas 67 degrees. After being shaped by the die lip, the extrudate wasquenched and drawn through a water tank and around an idler roll at aspeed of 6.4 meter/min with the water being maintained at approximately45° C. The web was air dried and collected into a roll. The resultingweb as depicted in FIG. 3 had a pronounced sinusoidal-type structurewith a partitioning of the white (A) and red (B & C) layers into anupper plane (peaks) and lower plane (valleys), respectively. The red (B& C) layers are depicted as 1 layer in FIG. 3 because the materialforming the two layers is identical and thus acts as 1 layer in thisembodiment. The basis weight, wavelength (w), amplitude (h) andthickness (t) of the sinusoidal shaped web as depicted in FIG. 3 a wasmeasured and is reported in Table 1 below.

EXAMPLE 2

A coextruded profiled web was made as in Example 1 except the extrudatewas drawn through the water tank and around an idler roll at a speed of9.5 meters/min. The tension of the web against the idler roll tended toflatten the overall sinusoidal structure. A significantly thinner,lighter weight web was produced having a relatively flat planarstructure with surface irregularities corresponding to the peak andvalley regions of the extrudate as it exited the die plate. The physicaldimensions of the web are shown in Table 1 below.

EXAMPLE 3

A coextruded profiled web was made as in Example 1 except the red ‘B’ &‘C’ layers were produced using a styrene-isoprene-styrene blockcopolymer (KRATON 1114, Kraton Polymers Inc., Houston, Tex.).Partitioning of the layers resulted in a web having elastic propertiesin the transverse direction and inelastic properties in the machinedirection. The physical dimensions of the web are shown in Table 1below.

TABLE 1 Example 1 Example 2 Example 3 Basis Weight (grams/meter²) 233155 239 Wavelength - w (microns) 660 635 660 Amplitude - h (microns) 890610 900 Thickness - t (microns) 220  90 185

1. A method for forming a thermoplastic polymeric film comprising: (a)combining two or more polymer melt streams forming a combined multilayermelt stream; (b) extruding the combined multilayer melt stream in a dieforming a substantially planar combined flowstream in the die having anupper zone and a lower zone; (c) extruding the substantially planarcombined flowstream through a die plate placed in a die outlet, the dieplate having a profiled film cut opening in a front face and adjacentwall portions, the profiled film cut opening having a plurality of peaksand valleys oscillating from an upper region to a lower region, wherethe substantially planar combined planar flowstream intersects the dieplate front face profiled film cut opening and adjacent wall portions,where the profiled film cut opening plurality of peaks and valleysdisproportionably partitions at least a portion of the polymer of thesubstantially planar combined flowstream in the upper zone to the upperregion and disproportionably partitions at least a portion of thepolymer of the substantially planar combined flowstream in the lowerzone to the lower region to form at least upper and lower polymer layersin a formed thermoplastic polymeric film; wherein at least one of thepolymer layers in the formed thermoplastic polymeric film varies inthickness across the formed film width due to the partitioning of thepolymer flow by the plurality of peaks and valleys of the opening, and(d) collecting the formed thermoplastic polymeric film, said formedthermoplastic polymeric film having a series of ridges extending aspeaks and valleys oscillating from a top surface to a bottom surface,which peaks and valleys extend in a first direction forming continuousridges, wherein the profiled cut opening is uniform in thickness acrossthe die plate.
 2. The method of claim 1 further comprising flatteningthe series of ridges extending as peaks and valleys oscillating from atop surface to a bottom surface of the formed film.
 3. The method ofclaim 1 wherein the formed film has no planar portions between the peaksand valleys.
 4. The method of claim 1 wherein the formed film has athickness of from 25 microns to 1000 microns.
 5. The method of claim 1wherein the formed film has a thickness of from 50 microns to 500microns.
 6. The method of claim 1 wherein the peaks extend in analternating fashion from a midline of the formed film to an outer plane.7. The method of claim 6 wherein the distance between the midline andthe upper plane is 50 microns to 2000 microns.
 8. The method of claim 5wherein the distance between the midline and the upper plane is 100microns to 1000 microns.
 9. The method of claim 1 wherein there are atleast 2 peaks per linear cm of the formed film.
 10. The method of claim1 wherein there are at least 5 peaks per linear cm of the formed film.11. The method of claim 1 further comprising cutting said formed film onat least one face in a second direction at an angle to said firstdirection at multiple cut lines at least through some of the peaks totheir undersides so as to form a plurality of cut portions, orientingsaid cut film in said first direction so as to separate said cutportions forming a set of separated strands connected by uncut portions.12. The method of claim 11 wherein the distance between cuts is 100microns to 1000 microns.
 13. The method of claim 11 wherein the distancebetween cuts is 200 microns to 500 microns.
 14. The method of claim 11wherein the cuts extend through the underside of the peaks at least to amidline of the formed film.
 15. The method of claim 11 wherein the cutsterminate as they reach the underside of substantially all of the peakson the opposing formed film face.
 16. The method of claim 11 wherein theformed film is cut on both faces in an alternating pattern where the cutlines on one face are offset from the cut lines on the opposing face.17. The method of claim 16 where the distance between the cuts on bothfaces is from 100 microns to 1000 microns.
 18. The method of claim 1wherein the formed film is stretched at a ratio of from 2:1 to 4:1. 19.The method of claim 11 further comprising orienting said cut film in asecond direction so as to biaxially orient said cut film.
 20. The methodof claim 1 wherein the at least one polymer layer varies in thicknessfrom its thinnest to its thickest zone portion such that it comprisesfrom 0-100% of the total film thickness across the width of the formedfilm.
 21. The method of claim 1 wherein the at least one polymer layervaries in thickness from thickest to thinnest zones by 10-100 percent.22. The method of claim 1 wherein the at least one polymer layer variesin thickness from thickest to thinnest zones by 10-90 percent.
 23. Themethod of claim 1 wherein the die plate comprises a sinusoidal profiledopening.
 24. The method of claim 1 wherein the die plate profiledopening comprises at least a section which is rectilinear.
 25. Themethod of claim 1, wherein combining two or more polymer melt streamsforming a combined multilayer melt stream comprises combining three ormore polymer melt streams, wherein at least one of the polymer layers inthe formed thermoplastic polymeric film remains substantially consistentin thickness across the formed film width due to the partitioning of thepolymer flow by the plurality of peaks and valleys of the opening.